Structures that comprise one or more elements that can be linked together to form a column or other structure are known in the art. Structures of this kind may be used to form an elevated platform for support of equipment or a person.
Extendable/retractable towers (or simply “retractable towers” as they may be referred to herein) of this kind may be utilized for surveillance, as mobile telecommunications towers, as supports for temporary lighting systems, or the like. In general, retractable columns or towers may be used for any application where it is desired to provide a support for a person or equipment at an elevated location relative to its surroundings.
Although existing retractable towers have been satisfactory for some applications, various shortcomings have limited their utility. For example, existing towers are often bulky, heavy and challenging to transport. This affects their ability to be delivered to remote locations where infra-structures such as bridges and roads do not exist or where infra-structures have been damaged or destroyed. Often, existing tower structures cannot be delivered until the infra-structures have first been repaired or replaced. Once a retractable tower is successfully delivered, it must still be erected. With existing retractable towers this can take upwards of 1-2 hours or longer because they often require that the erection site must be prepared and improved. Moreover, existing tower drive mechanisms are not capable of high speed operation. This presents a significant drawback where time is of the essence, such as in the wake of a natural disaster where critical services such as emergency communications need to be immediately reestablished or when monitoring a hostile, armed enemy under wartime conditions. Often, existing retractable towers will not be able to support a required payload or withstand significant wind loads unless first stabilized by a series of guy wires that prevent the tower from toppling and/or collapsing. Such additional requirements and their implementation can add significant setup time. Many existing retractable towers are often fabricated from parts that, when in motion, generate significant noise levels, which can be detrimental in situations where stealth is required. Once an existing retractable tower has been erected and operational, there is usually nothing to protect the internal mechanical and electrical components from the environment, animals, etc. over what may be an extended time period. This is a drawback where a retractable tower must operate autonomously and is deployed for an extended period of time in a remote location. With existing retractable towers, it often takes as much time to retract the tower as it does to erect it. This makes deployment and redeployment a long, time consuming process. This also presents a significant drawback because a tower may need to be refitted with different sensors, antennas, lighting, etc. or where the tower is in imminent danger of capture or destruction from a hostile enemy. Accordingly, there is a need in the art for an extendable and retractable tower or column structure that addresses these drawbacks.